Method for producing food grade poultry oil and meal

ABSTRACT

A method and apparatus for producing increased protein chicken meal. Scrap chicken parts are loaded into a cooking vat that is 40 feet long by 5 feet wide by 4 feet deep, with a system of moving chain conveyors and paddles. These conveyors move the scrap chicken parts at a predetermined speed through oil maintained at a temperature of approximately 360° to 380° F. for the entire length of the vessel, and dump the scrap chicken parts at the opposite end of entry. Oil is circulated through the vat at a rate of approximately 680 to 860 gallons per minute (gpm) to allow for the rapid removal of fat and moisture from skin and meat in a continuous process. The scrap chicken parts are removed from the vat and pressed to form poultry oil. Subsequently, the scrap chicken parts are broken up to form a high protein chicken meal.

FIELD OF THE INVENTION

The present invention relates to the rendering of food grade poultry oiland meal, from the leaf fat, skin, necks and backs of chicken carcasses.The overall arrangement includes an improved apparatus for carrying outthis method as well as a new system of product flow.

BACKGROUND OF THE INVENTION

Various practices have been performed in the past to produce a usableproduct from the scraps of slaughtering operations. Examples of some ofthese practices are found in U.S. Pat. No. 2,019,547 to Theobald, U.S.Pat. No. 3,295,982 to Hickey et al., U.S. Pat. No. 3,345,353 to Klubien,U.S. Pat. No. 3,346,393 to Bradford, U.S. Pat. No. 4,361,590 to Wojcikand U.S. Pat. No. 4,565,709 to Berge et al.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amethod and apparatus for producing increased protein chicken meal. Thisobject is accomplished by initially having all product to be rendereddelivered to a cooking facility in portable vats. The delivered productis maintained at a temperature below 55° F. This assures that all endproducts produced will meet U.S. Department of Agriculture foodrequirements.

Product is then loaded into a mechanical dumper, which in turn loadsproduct onto a variable speed belt. Product that contains bones andgristle are sent through a rough chopper or screen. The acceptableproduct is then moved by conveyor to and dumped into a cooking vat at arate of approximately 10,000 to 12,000 pounds per hour.

The cooking vat is a vessel that is 40 feet long by 5 feet wide by 4feet deep, with a system of moving chain conveyors and paddles. Theseconveyors move the product at a predetermined speed through oilmaintained at a temperature of approximately 360° to 380° F. for theentire length of the vessel, and dumps the product at the opposite endof entry. The amount of required contact time with the heated oil isdetermined by the type of product, or product mix being loaded into thecooker.

The cooking vat is designed such that oil is circulated through the vatat a rate of approximately 680 to 860 gallons per minute (gpm) to allowfor the rapid removal of fat and moisture from skin and meat in acontinuous process. The volume of oil in the cooking vat isapproximately 4,500 gallons. Additional inlets and outlets for oil maybe added to the vat to allow for the tremendous flow of oil required tomaintain a frying temperature.

Step one of the cooking process is the loading of product into the vat.This is accomplished with an elevated conveyor that delivers the productto be cooked at a continuous rate. This rate can be varied by theimplementation of a variable speed control panel. Speed variance at thispoint will allow a controlled loading of the cooking vat, thereforeallowing the cooking time to be adjusted according to an assorted supplyof products.

After the product is delivered to the tank a series of paddles move thecooking product the entire length of the vat. The paddles are connectedto a drive chain that is driven by a constantly variable speed hydraulicdrive unit. Paddles and chains are guided by a continuous length set ofguides, made up of stainless steel angles.

The chain is led into the guides by a set of eight large cog wheels, twodriven and six idlers. The idlers on the top of the tank are connectedtogether and the lower idlers run independent of each other. As thechains and paddles emerge from the discharge end of the tank, the cookedproduct is dumped from the vat into a conveyor to carry it onto the nextstep of the process. Paddles return to the beginning of the processalong slides mounted on the top of the tank.

The product is cooked through a direct contact with heated oil. This oilis approximately three feet deep in the vat. Oil is circulated throughthe tank at a preferable temperature of 380 degrees and at a preferablevelocity of 860 gpm. The oil enters the vat through a series of inletpipes on both sides of the tank. These six inch diameter lines enter thetank at a 221/2 degree angle, canted towards the discharge end of thevat. The angle of the pipes will assist in moving oil from one end onthrough the vat.

Oil is removed from the vat through a ten inch diameter pipe in thedischarge end. To reduce the amount of solids entering the heatexchanger, a high speed rotating screen is installed on the dischargeend to remove smaller particles. The rotating screen is cleaned byinstallation of an air line and a constant flow of air being dischargedthrough the screen. Larger particles are contained in the vat with ascreen. As the paddles pass this screen, a wiper strip attached to thebottom of each paddle, wipes away the product being drawn to the screen.The wiper strip includes a TEFLON non-stick coating.

Heated oil is removed from the vat and is later supplied back to thecooking vat via a pump station that delivers the oil through a cyclonicliquid filter to remove the suspended particles of cooked fat and on toa direct fired heat exchanger. From the heat exchanger, where the oil ispreferably reheated to 380 degrees, the oil is returned to the cookingvat at a preferable rate of 860 gallons per minute.

The constant exchange of oil and the temperatures to which the oil isheated, are designed to improve the release of oil and fat from theproduct so that the moisture level is approximately 12% in the productand the fat content is broken down. Moisture is released into theatmosphere through a vented hood that covers the entire cooking vat. Acontinuous oil level is maintained by the implementation of a weir andstrainer, where oil and fat are picked up, pumped through a Stein filterand then through a Star filter for cleaning and polishing and thenpumped into a holding tank to await transporting.

The superior quality of the end product is due to the cooking method andtemperatures maintained while cooking, in combination with the freshnessmaintained prior to cooking.

The solid product is conveyed out of the cooking vat into a screw augerand then transported to another screw auger. From the last mentionedscrew auger, product is delivered to a hydraulic driven Dupps presswhich removes any excess oil above approximately 8% from the solids.Drain plugs exist under the screw augers to capture oil from solidsduring conveying periods. The captured oil is returned to the pumpstation. This process will help eliminate unnecessary oil going to theDupps press.

Oil extracted by the Dupps press is pumped to a sedimentation tank.After a period of time, oil in the sedimentation tank is pumped to theStein filter, Star filter, and on to the oil storage tank. Solids fromthe sedimentation tank are removed by a screw auger, and placed onanother screw auger. At this point, solids are returned to the screwauger leading to the Dupps press and the process is repeated through theDupps press and the sedimentation tank.

Solids from the Dupps press in the form of a ribbon-like product, areremoved by an additional screw auger and placed on another screw auger.After a cooling process, the last mentioned screw auger delivers solidsto a hammer mill. Inside the hammer mill, solids are crushed and groundto a fine meal. Finished meal will then be augured to a meal storagetank to await transporting. The protein content of the finished mealwill be higher than regular poultry meal, and the ash content will bevery low due to the absence of bone in the mix.

It is therefore another object of the present invention to processdiscarded pieces from a chicken slaughtering operation to produce a highquality, high protein chicken meal.

It is still another object of the present invention to cook discardedportions of a chicken slaughtering operation in a vat of heated oil,with the oil rapidly moved through the vat and with the chicken piecesbeing transported through the vat for removal of fat and moisture.

Still yet another object of the present invention involves the cookingof discarded portions of a chicken slaughtering operation in a vathaving constantly circulated oil heated to a temperature in the range of360° to 380° F., with oil being removed and input into the vat at a rateof 680 to 860 gallons per minute.

It is still yet another object of the present invention to removemoisture and fat from discarded portions of a chicken slaughteringoperation by cooking the chicken portions in a vat of oil heated to apreferable temperature of 380° F. with the oil circulating through thevat at a preferable rate of 860 gallons per minute so as to ultimatelyproduce a high quality, high protein chicken meal.

These and other objects of the invention, as well as many of theintended advantages thereof, will become more readily apparent whenreference is made to the following description taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic floor plan of the apparatus for performing themethod of the present invention.

FIG. 2 is a sectional view of the cooking vat shown in FIG. 1.

FIG. 3 is a plan view of the cooking vat shown in FIG. 2.

FIG. 4 is an enlarged plan view of the paddle shown in the cooking vatof FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing a preferred embodiment of the invention illustrated in thedrawings, specific terminology will be resorted to for the sake ofclarity. However, the invention is not intended to be limited to thespecific terms so selected, and it is to be understood that eachspecific term includes all technical equivalents which operate in asimilar manner to accomplish a similar purpose.

With reference to the drawings, in general, and to FIG. 1, inparticular, a system for conducting a method of producing food gradepoultry oil and meal is generally designated as 10. With reference toits orientation in FIG. 1, the required apparatus is primarily housedwithin a building 12 having a loading dock 14.

Discarded chicken portions from a chicken slaughtering operation aretransported in portable containers by truck and delivered to building 12at the truck dock 14 through entrance 16. The food product is maintainedat a temperature below 55° F. to ensure food quality.

The delivered food product is then transported to a dumper mechanism 18which inverts the food containers and dumps its contents onto aninclined variable speed belt conveyer 20. The conveyer 20 as illustratedin FIGS. 2 and 3, includes a plurality of rollers 22 about which extendsa continuous belt 24. The rollers 22 are driven by a motor 26 having apulley 28 connected to a leading roller 30 so as to turn the belt 24 andconvey food product between vertically rising guide walls 32.

The product moved by inclined conveyor 20 is dumped into the cooking vat34 along guide 36. The cooking vat 34 includes a drive chain belt 38 towhich are connected a plurality of equally spaced extension arms 40,terminating in paddles 42, for conveying food product through thecooking vat.

The chain belt 38 extends across the vat 34 and between two drive cogwheels 44 which are driven by a constantly variable speed, hydraulicdrive unit 46 through a drive shaft 48 passing through the center of thedrive cog wheels 44. The chain belt 38 is also passed around three setsof idler cog wheels 50, 52 and 54. The idler cog wheels 50 are connectedtogether by a shaft 56 (similar to the arrangement for drive cog wheels44) whereas the idler cog wheel sets 52 and 54 run independently of eachother.

The chain belt 38 extending across the width of the cooking vat 34,passes, at its edges, between stainless steel angle guides 58, withinthe vat, which includes a layer of TEFLON nonstick coating. Above thecooking vat 34, the chain belt is guided by horizontally orientedsupport 60 braced above the vat by legs 62.

In the cooking vat 34, at its inlet end 64, is located a six inchdiameter inlet pipe 66 which leads to an elongated pipe 68 having aplurality of openings 70, with a pipe 68 leading off of the inlet pipe66 on opposite sides of the cooking vat. Heated oil passes throughopenings 70 in a direction towards the discharge end 72 of the cookingvat 34 at an angle of approximately 22.5°. Oil directed through theopenings 70 will therefore be directed towards the discharge end and aidin conveying food product through the cooking vat, below the oil level74, for total contact, heating and cooking of the food product beingprocessed. At the discharge end 72 of the cooking vat 34, there is a 10inch diameter outlet pipe 76 for removal of oil from the cooking vat.

As the paddles 42 move through the oil in the cooking vat, in thedirection from the inlet end 64 to the discharge end 72, food product isconveyed up along a screen 78 located at the discharge end 72. Smallerparticles of food product and/or fat passing through the screenencounter a high speed rotating screen 80 having short projections 82 tomove the smaller particles passing through screen 78 so as to preventthe small particles from entering the outlet pipe 76. The rotatingscreen 80 is cleaned by an air line outlet 84 which provides a constantflow of air discharged through the screen.

As the paddles pass over the screen 78, a TEFLON no-stick coating wiperstrip 86, wipes product being drawn to the screen to the discharge end72 of the cooking vat. It is understood as being within the scope of thepresent invention to have a plurality of paddles 42 spaced laterallyacross the chain conveyor 38 so as to move food product through thecooking vat. Each of the paddles 42 may be interconnected by projections86 extending laterally from the side edges of the paddles 42.

Returning to FIG. 1, in the operation of the cooking vat 34, oilwithdrawn from outlet pipe 76 is conveyed by conduit 88 to a pumpstation 90. The pump station divides a small portion of the heated oilfrom the main supply of extracted oil and passes this small oil portionthrough conduit 92, to a heat exchanger 94 which transfers some of theheat from the oil to heat water to be stored in a hot water tank 96. Thehot water tank 96 is used with a high pressure pump 98 in a cleaningoperation of the apparatus of the present invention. After transfer ofheat in heat exchanger 94 to water to be stored in tank 96, the oil isreturned by conduit 100 to the pump station 90.

The majority of oil withdrawn through outlet pipe 76 and the oilreturned by conduit 100 back to the pump station 90 is transferred byconduit 102 to a LATCO cyclonic liquid filter 104 for removal ofsuspended particles of cooked fat in the oil. The cooked fat particlesseparated from the oil are transferred by conduit 106 for subsequentprocessing.

The filtered oil is then transferred by conduit 108, to a direct firedheat exchanger 110. At the heat exchanger 110, the oil is heated to atemperature in the range of 360° to 380°, and preferably 380°. Theheated oil is then transferred by conduit 112 to the inlet pipe 66 atthe inlet end 64 of the cooking vat 34.

The pumps 114 in the pumping station 90 withdraw oil from the cookingvat and return oil to the cooking vat at a rate of 680 to 860 gpm. Thisvery rapid movement of oil through the cooking vat, at elevatedtemperatures, provides for a high protein content meal due to theremoval of moisture and fat from the chicken pieces being processed.

In addition, a continuous oil level is maintained by a weir and strainer116 which siphons oil and fat from an upper surface of the oil in thecooking vat and transfers the extracted oil and fat through conduit 118.Conduit 118 passes to a STEIN filter 120 and then through conduit 122 toa STAR filter 124 for cleaning and polishing of the oil prior to the oilbeing conveyed through conduit 126 to an oil storage tank 128.

Returning to the further processing of the food product conveyed throughthe cooking vat 34 by paddles 42 and the force of heated oil directedtowards the discharge end 72, the solid product is conveyed by a screwauger conveyor 130 in a direction perpendicular to the direction ofextension of the cooking vat 34. The solid product is delivered toanother screw auger conveyor 132 which extends perpendicular to theconveyor 130. Excess oil is allowed to drain from the solid product asthe product is conveyed along conveyors 130 and 132.

The solid product is then delivered to a press 134 which compresses thesolid product to remove any excess oil. The oil removed by the press 130is conveyed by conduit 136 to a sedimentation tank 138. In addition, thesuspended particles of cooked fat removed by the filter 104 are conveyedthrough conduit 106 to the sedimentation tank 138 for furtherprocessing. Oil separated from solid product in the sedimentation tankis removed by conduit 140 and delivered to the filters 120 and 124 forultimate delivery to the storage tank 128.

The solid product from the sedimentation tank is moved by screw augerconveyor 141 to another screw auger conveyor 142 and return deliveryback to the screw auger 132 and return delivery to the press 134. Therecycling of solid product through the press 134 ensures maximum oilremoval from the solid product.

Solid product produced by the press 134 is transferred by screw augerconveyor 144 to screw auger conveyor 146 and delivery to a hammer mill148. At hammer mill 148, dry solid product is crushed and ground into afine chicken meal. The chicken meal is conveyed by screw auger conveyors150 and 152 to a meal storage tank 154.

By the method using the apparatus described, a high quality food productis produced with a high protein content. This superior product resultsfrom the continuous extraction of fat and moisture by cooking in hightemperature oil with continuous subsequent removal of the oil from thecooked food product.

The foregoing description should be considered as illustrative only ofthe principles of the invention. Since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and, accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

We claim:
 1. A process of removing fat, edible oil and moisture fromscrap chicken parts, said process comprising:cooking the scrap chickenparts in a vat of cooking oil heated to a temperature in the range of360° to 380° F., transporting the scrap chicken parts through the vat ofcooking oil, removing the cooking oil from the vat and reheating thecooking oil prior to returning the cooking oil to the vat at an elevatedtemperature, removing the cooked scrap chicken parts from the vat,pressing the cooked scrap chicken parts to remove poultry oil, andbreaking up the pressed and cooked scrap chicken parts to form a highprotein, low ash content chicken meal.
 2. A process according to claim1, wherein the oil is returned to the vat at a rate of 680 to 860gallons per minute.
 3. A process according to claim 1, wherein the oilis returned to the vat in a direction which is in the same direction asthe chicken parts are transported through the vat.
 4. A processaccording to claim 1, wherein oil is siphoned off from an upper surfaceof the oil to remove fat released by the chicken parts.
 5. A processaccording to claim 1, wherein a conveyor having paddles transports thechicken parts through the vat.
 6. A process according to claim 1,wherein oil is removed from a discharge end of the vat and oil isreturned to an inlet end of the vat.
 7. A process as claimed in claim 1,wherein the breaking up of the pressed and cooked scrap chicken parts isperformed by crushing and grinding.
 8. A process as claimed in claim 1,wherein the pressed and cooked scrap chicken parts are cooled prior tobreaking up.
 9. A process as claimed in claim 1, where scrap chickenparts are delivered into the vat at a temperature below 55° F.
 10. Aprocess as claimed in claim 1, wherein scrap chicken parts containingbone and gristle are processed through a rough chopper or screen priorto cooking.
 11. A process of removing fat, edible oil and moisture fromscrap chicken parts, said process comprising:cooking the scrap chickenparts in a vat of cooking oil heated to a temperature in the range of360° to 380° F., transporting the scrap chicken parts through the vat ofcooking oil, removing the cooking oil from the vat and reheating thecooking oil prior to returning the cooking oil to the vat at an elevatedtemperature, removing the cooked scrap chicken parts from the vat,pressing the cooked scrap chicken parts to remove poultry oil, breakingup the pressed and cooked scrap chicken parts to form a high proteinchicken meal, conveying the poultry oil to a sedimentation tank forprocessing for a predetermined amount of time, removing the poultry oilfrom the sedimentation tank after the predetermined amount of time, andcleaning and polishing the removed poultry oil to form food gradepoultry oil.
 12. A process of removing fat, edible oil and moisture fromscrap chicken parts, said process comprising:cooking the scrap chickenparts in a vat of cooking oil heated to a temperature in the range of360° to 380° F., transporting the scrap chicken parts through the vat ofcooking oil, removing the cooking oil from the vat and reheating thecooking oil prior to returning the cooking oil to the vat at an elevatedtemperature, removing the cooked scrap chicken parts from the vat,pressing the cooked scrap chicken parts to remove poultry oil, andbreaking up the pressed and cooked scrap chicken parts to form a highprotein chicken meal, filtering the removed cooking oil to removesuspended particles of cooked chicken fat, conveying the cooked chickenfat obtained by filtering the cooking oil to a sedimentation tank forprocessing for a predetermined amount of time, the sedimentation tankincluding poultry oil obtained from pressing cooked scrap chicken partsremoved from the vat, removing the poultry oil from the sedimentationtank after the predetermined amount of time, and cleaning and polishingthe removed poultry oil to form food grade poultry oil.
 13. A process ofremoving fat, edible oil and moisture from scrap chicken parts, saidprocess comprising:cooking the scrap chicken parts in a vat of cookingoil heated to a temperature in the range of 360° to 380° F.,transporting the scrap chicken parts through the vat of cooking oil,withdrawing poultry oil from an upper surface of the cooking oil,cleaning and polishing the withdrawn poultry oil to form food gradepoultry oil, removing the cooking oil from the vat and reheating thecooking oil to returning the cooking oil to the vat at an elevatedtemperature, removing the cooked scrap chicken parts from the vat, andbreaking up the pressed and cooked scrap chicken parts to form a highprotein, low ash content chicken meal.
 14. A process of removing fat,edible oil and moisture from scrap chicken parts, said processcomprising:cooking the scrap chicken parts in a vat of cooking oilheated to a temperature in the range of 360° to 380° F., transportingthe scrap chicken parts through the vat of cooking oil, removing thecooking oil from the vat and reheating the cooking oil prior toreturning the cooking oil to the vat at an elevated temperature,removing the cooked scrap chicken parts from the vat, pressing thecooked scrap chicken parts to remove poultry oil, breaking up thepressed and cooked scrap chicken parts to form a high protein chickenmeal, conveying the poultry oil to a sedimentation tank for processingfor a predetermined amount of time, removing the poultry oil from thesedimentation tank after the predetermined amount of time, cleaning andpolishing the removed poultry oil to form food grade poultry oil,removing solid product from the sedimentation tank, pressing the removedsolid product and crushing and grinding the pressed product to form ahigh protein chicken meal.